System and method for beamformed reference signals in three dimensional multiple input multiple output communications systems

• US 10,154,496 B2
• Filed: 02/27/2017
• Issued: 12/11/2018
• Est. Priority Date: 11/10/2016
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Stirling-Gallacher, Richard
• Primary Examiner(s): Bhatti, Hashim S
• Application Number:
  US15/443,066
• Publication Number:
  US 20180132217A1
• Time in Patent Office: 652 Days
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0486 taking channel rank into account
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams

Abstract

A method for operating a transmission point includes transmitting a plurality of first directional reference signals and a plurality of second directional reference signals, the plurality of first directional reference signals sweeping different first beams in a first plane and the plurality of second directional reference signals sweeping different first beams of the first plane, and receiving from a reception point, a request for the transmission point to commence operations in the second plane and a first feedback from a reception point, the first feedback indicating at least one first beam of the first plane and at least one beam group of the second plane, where measurements of the at least one first beam and the at least one beam group of the second plane satisfy a first selection criterion.

Claims

1. A method for operating a transmission point, the method comprising:

transmitting, by the transmission point, a plurality of first directional reference signals, the plurality of first directional reference signals sweeping different first beams in a first plane which are constrained by a first beam group of a second plane;

transmitting, by the transmission point, a plurality of second directional reference signals, the plurality of second directional reference signals sweeping the different first beams of the first plane which are constrained by a second beam group of the second plane;

receiving from a reception point, by the transmission point, a request for the transmission point to commence operations in the second plane and a first feedback, the first feedback indicating at least one first beam of the first plane and at least one beam group of the second plane, where measurements of reference signals in the at least one first beam and the at least one beam group of the second plane satisfy a first selection criterion; and

when the transmission point is capable of performing beam sweeping in the second plane,

transmitting, by the transmission point, a plurality of third directional reference signals, the plurality of third directional reference signals oriented in accordance with the at least one first beam and sweeping in the at least one beam group of the second plane, and

receiving, by the transmission point, a second feedback from the reception point, the second feedback indicating that at least one third directional reference signal meets a second selection criterion.

2. The method of claim 1, further comprising transmitting first configuration information for the first and second directional reference signals transmitted in the first plane, the first configuration information includes at least one of a number of directional reference signals in each plane, a number of repetitions of the first and second directional reference signals in each plane, an indication of a feedback method for the reception point, a downlink transmission capability of the transmission point, a configuration of beam groups in the second plane, and a resource location for the directional reference signals.

3. The method of claim 1, further comprising transmitting second configuration information for the third directional reference signals transmitted in the second plane, the second configuration information includes at least one of a number of different first plane beams, a number of second plane beams for each first plane beam, a number of reference signal repetitions per second plane beam, resource locations of different reference signals, a feedback method indicator, and a maximum rank of the transmission point in the second plane.

4. The method of claim 1, wherein the second feedback comprises channel quality indicators for the at least one third directional reference signal, and wherein the method further comprises:

selecting transmission parameters in accordance with the channel quality indicators; and

transmitting an indication of the transmission parameters to the reception point.

5. The method of claim 4, wherein the indication of the transmission parameters comprises at least one of a modulation and coding scheme (MCS) level, a beam index of a directional reference signal selected in accordance with the channel quality indicators, a precoding matrix indicator (PMI), and a rank indicator (RI).

6. The method of claim 1, further comprising when the transmission point is incapable of performing beam sweeping in the second plane:

transmitting a beamformed reference signal configuration to the reception point, the beamformed reference signal configuration including an indication that the transmission point is not capable of operations in the second plane.

7. The method of claim 6, further comprising transmitting data to the reception point in accordance with the first feedback.

8. The method of claim 1, further comprising:

receiving a start data transmission request from the reception point, the start data transmission request indicating to the transmission point to commence communications with the reception point in accordance with the first feedback; and

transmitting information to the reception point in accordance with the first feedback.

9. A method for operating a reception point, the method comprising:

receiving, by the reception point, a plurality of first directional reference signals and a plurality of second directional reference signals, the plurality of first directional reference signals sweeping different first beams in a first plane which are constrained by a first beam group of a second plane, the plurality of second directional reference signals sweeping the different first beams of the first plane which are constrained by a second beam group of the second plane;

selecting, by the reception point, at least one first selected directional reference signal from at least one of the plurality of first and second directional reference signals that meets a first selection criterion, and at least one beam group associated with the at least one first selected directional reference signal; and

transmitting, by the reception point, a first feedback indicating the at least one first selected directional reference signal and the at least one beam group associated with the at least one first selected directional reference signal.

10. The method of claim 9, further comprising:

receiving, by the reception point, a plurality of third directional reference signals sweeping the at least one beam group as indicated in the first feedback;

selecting, by the reception point, at least one second selected directional reference signal from the plurality of third directional reference signals that meet a second selection criterion; and

transmitting, by the reception point, a second feedback indicating the at least one second selected directional reference signal.

11. The method of claim 10, wherein the second feedback also indicates channel quality indicators for the at least one second selected directional reference signal.

12. The method of claim 10, wherein the second feedback comprises beam indices corresponding to directional reference signals in a first subset of the at least one first selected directional reference signal and the at least one second selected directional reference signal.

13. The method of claim 10, wherein the second feedback comprises at least one of a first precoding matrix indicator for a first subset of the at least one first selected directional reference signal and a second precoding matrix indicator for the at least one second selected directional reference signal.

14. The method of claim 10, wherein each one of the first selection criterion and the second selection criterion comprises one of a received signal strength, a signal to noise ratio (SNR), a signal to interference plus noise ratio (SINR), and a channel capacity.

15. The method of claim 9, further comprising receiving configuration information for directional reference signals in the first and second planes, the configuration information including at least one of a number of directional reference signals in each plane, a number of repetitions of the directional reference signals in each plane, an indicator of a feedback method for the reception point, a downlink transmission capability of a transmission point, a configuration of beam groups in the second plane, and a resource location for the directional reference signals.

16. A transmission point comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to configure the transmission point to;

transmit a plurality of first directional reference signals, the plurality of first directional reference signals sweeping different first beams in a first plane which are constrained by a first beam group of a second plane,

transmit a plurality of second directional reference signals, the plurality of second directional reference signals sweeping the different first beams of the first plane which are constrained by a second beam group of the second plane,

receive, from a reception point, a request for the transmission point to commence operations in the second plane and a first feedback, the first feedback indicating at least one first beam of the first plane and at least one beam group of the second plane, where measurements of reference signals in the at least one first beam and the at least one beam group of the second plane satisfy a first selection criterion, and

when the transmission point is capable of performing beam sweeping in the second plane,

transmit a plurality of third directional reference signals, the plurality of third directional reference signals oriented in accordance with the at least one first beam and sweeping in the at least one beam group of the second plane, and

receive a second feedback from the reception point, the second feedback indicating that at least one third directional reference signal meets a second selection criterion.

17. The transmission point of claim 16, wherein the programming includes instructions to configure the transmission point to transmit first configuration information for the first and second directional reference signals transmitted in the first plane, the first configuration information includes at least one of a number of directional reference signals in each plane, a number of repetitions of the first and second directional reference signals in each plane, an indication of a feedback method for the reception point, a downlink transmission capability of the transmission point, a configuration of beam groups in the second plane, and a resource location for the directional reference signals.

18. The transmission point of claim 16, wherein the second feedback comprises channel quality indicators for the at least one third directional reference signal, and wherein the programming includes instructions to configure the transmission point to select transmission parameters in accordance with the channel quality indicators, and transmit an indication of the transmission parameters to the reception point.

19. The transmission point of claim 18, wherein the indication of the transmission parameters comprises at least one of a modulation and coding scheme (MCS) level, a beam index of a directional reference signal selected in accordance with the channel quality indicators, a precoding matrix indicator (PMI), and a rank indicator (RI).

20. The transmission point of claim 16, wherein the programming includes instructions to configure the transmission point to, when the transmission point is incapable of performing beam sweeping in the second plane, transmit a beamformed reference signal configuration to the reception point, the beamformed reference signal configuration including an indication that the transmission point is not capable of operations in the second plane.

21. The transmission point of claim 16, wherein the programming includes instructions to configure the transmission point to receive a start data transmission request from the reception point, the start data transmission request indicating to the transmission point to commence communications with the reception point in accordance with the first feedback, and transmit information to the reception point in accordance with the first feedback.

22. A reception point comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to configure the reception point to;

receive a plurality of first directional reference signals and a plurality of second directional reference signals, the plurality of first directional reference signals sweeping different first beams in a first plane which are constrained by a first beam group of a second plane, the plurality of second directional reference signals sweeping the different first beams of the first plane which are constrained by a second beam group of the second plane,

select at least one first selected directional reference signal from at least one of the plurality of first and second directional reference signals that meets a first selection criterion, and at least one beam group associated with the at least one first selected directional reference signal, and

transmit a first feedback indicating the at least one first selected directional reference signal and the at least one beam group associated with the at least one first selected directional reference signal.

23. The reception point of claim 22, wherein the programming includes instructions to configure the reception point to receive a plurality of third directional reference signals sweeping the at least one beam group as indicated in the first feedback, select at least one second selected directional reference signal from the plurality of third directional reference signals that meet a second selection criterion, and transmit a second feedback indicating the at least one second selected directional reference signal.

24. The reception point of claim 22, wherein the programming includes instructions to configure the reception point to receive configuration information for directional reference signals in the first and second planes, the configuration information including at least one of a number of directional reference signals in each plane, a number of repetitions of the directional reference signals in each plane, an indicator of a feedback method for the reception point, a downlink transmission capability of a transmission point, a configuration of beam groups in the second plane, and a resource location for the directional reference signals.